Molding system

Abstract

This molding system comprises: a heating unit for heating a metal pipe material; and a molding unit for molding the heated metal pipe material. The molding unit is provided with a quenching mechanism for quenching a molded article. The molded article is transported to a cooling mechanism, which is separate from the quenching mechanism, in the middle of quenching by the quenching mechanism.

Description

Molding System

[0001] The present disclosure relates to a molding system.

[0002] A conventional forming system is disclosed in Patent Document 1. This forming system heats a metal pipe material and forms the heated metal pipe material in a forming die, thereby forming the shape of the metal pipe material into the shape of the forming surface of the forming die. In addition, the metal pipe material is quenched simultaneously with the forming.

[0003] Japanese Patent Application Laid-Open No. 2009-220141

[0004] In the heating, forming, and quenching processes described in the aforementioned Patent Document 1, a metal pipe material is heated to the austenite region, and then the metal pipe material is brought into contact with a mold to be formed, thereby performing quenching and forming at a predetermined cooling rate, thereby achieving the target mechanical properties and dimensional accuracy. However, to achieve the target mechanical properties and dimensional accuracy, the formed product is removed from the mold after the temperature reaches or falls below the martensitic transformation finish temperature (Mf point). This results in a problem of a long throughput until the formed product is removed from the mold, and a long occupation time for one metal pipe material in the forming device.

[0005] On the other hand, if a molded product is removed from the mold immediately after molding and allowed to cool in the air to improve throughput, the cooling rate will vary depending on the part with an irregular cross-section, making it impossible to obtain the cooling rate required for martensitic transformation and preventing the molded product from achieving the desired strength as a whole. Furthermore, the cooling start temperature and cooling rate of each part of the molded product will be uneven, resulting in warpage due to differences in the amount of thermal shrinkage in each part, making it impossible to achieve the desired dimensional accuracy.

[0006] One aspect of the present disclosure has been made to solve such problems, and aims to provide a molding system that can shorten molding throughput while obtaining the desired strength of the molded product.

[0007] A forming system according to one embodiment of the present disclosure includes a heating unit that heats a metal pipe material and a forming unit that forms the heated metal pipe material, and the forming unit is provided with a quenching mechanism that quenches the formed product, and the formed product is transported to a cooling mechanism separate from the quenching mechanism during quenching by the quenching mechanism.

[0008] In the molding system, the molding section is provided with a quenching mechanism that quenches the molded product. Therefore, immediately after molding, the molded product is rapidly cooled by the quenching mechanism. Here, the molded product is transported to a cooling mechanism separate from the quenching mechanism while being quenched by the quenching mechanism. As a result, the molded product is rapidly cooled by the cooling mechanism, thereby completing the quenching. Therefore, the desired strength of the molded product can be obtained by quenching. In addition, the cooling mechanism is a mechanism separate from the quenching mechanism. Therefore, the throughput until the molded product is removed from the mold is shortened, and the quenching mechanism of the mold is able to mold the next metal pipe material. As described above, the molding throughput can be shortened while obtaining the desired strength of the molded product.

[0009] After being transferred to the separate cooling mechanism, the metal pipe material may be cooled from the martensitic transformation start temperature to the martensitic transformation finish temperature, thereby completing the quenching of the metal pipe material in the separate cooling mechanism.

[0010] The cooling mechanism may be a jig for cooling the molded product. In this case, the cooling mechanism can be installed in a location separate from the mold. Therefore, it is not necessary to provide a separate cooling mechanism in addition to the quenching mechanism in the mold itself.

[0011] The quenching mechanism and the cooling mechanism may be provided at different positions within the same mold, in which case there is no need to secure space for the cooling mechanism outside the mold.

[0012] In the forming section, the metal pipe material is expanded by supplying a fluid to it, and in the case of a metal pipe material with a low blow pressure in the forming section, the ratio of the cooling time in the cooling mechanism to the cooling time in the forming mold may be made higher than in the case of a metal pipe material with a high blow pressure. In this case, the shape can be firmly frozen even for metal pipe material with a low blow pressure.

[0013] According to one embodiment of the present disclosure, a molding system can be provided that can shorten molding throughput while ensuring dimensional accuracy of molded products.

[0014] 1 is a block diagram showing the configuration of a molding system according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram showing a specific example of the molding system shown in FIG. 1. FIG. 3 is a schematic diagram showing a specific example of the molding system shown in FIG. 1. FIG. 4 is a schematic diagram showing a specific example of the molding system shown in FIG. 1. FIG. 5 is a diagram showing a specific example of a cooling jig. FIG. 6 is a diagram showing a specific example of a cooling jig. FIG. 7 is a CCT diagram showing the cooling process of each process. FIG. 8 is a diagram showing a molding die of a molding system shown in a modified example. FIG. 9 is a diagram showing an example of another molded product. FIG. 10 is a graph showing the relationship between the temperature of the flat part of a molded product after air blowing and the blow retention time in the molding die due to differences in blow pressure. FIG. 11 is a graph showing the relationship between the cooling method and time for a molded product in a comparative example and an example, and FIG. 12 is a graph showing the proportion of cooling time by the molding die and the proportion of cooling time by the cooling mechanism, based on the total cooling time.

[0015] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be omitted.

[0016] Fig. 1 is a block diagram showing the configuration of a molding system 100 according to this embodiment. Figs. 2 to 4 are schematic configuration diagrams showing specific examples of the molding system 100 shown in Fig. 1.

[0017] The forming system 100 is a system for manufacturing a formed product 140 (see FIG. 4) by heating a metal material and forming the heated metal material in a forming die. As the metal material, a pipe-shaped metal pipe material 40 as shown in FIG. 2 or a plate-shaped metal material 50 as shown in FIG. 3 is used. As the metal material, for example, a carbon steel material or an MnB steel material with improved hardenability is used.

[0018] As shown in FIG. 1, the molding system 100 includes a heating section 101 , a molding device 103 (molding section) having a mold 102 , and a cooling mechanism 104 .

[0019] The heating unit 101 heats the metal material by passing an electric current through it. The heating unit 101 includes electrodes that contact the metal material to pass the electric current, and a power source that passes the electric current to the electrodes. As a result, the metal material itself generates heat through Joule heat due to its own electrical resistance (electrical heating). The molding device 103 is a device that molds the metal material heated by the heating unit 101 using a molding die 102.

[0020] For example, the forming device 103 may have the configuration shown in Fig. 2. The forming device 103 shown in Fig. 2 is a device that performs forming and quenching by supplying a fluid to a heated metal pipe material 40 and bringing it into contact with the forming surface of a forming die. This forming device 103 is equipped with a heating unit 101.

[0021] As shown in FIG. 2 , the molding device 103 is an apparatus for molding a metal pipe having a hollow shape by blow molding. Here, the molding device 103 is installed on a horizontal surface. The molding device 103 includes a molding die 102, a drive mechanism 3, a holding unit 4, a heating unit 101, a fluid supply unit 6, a cooling unit 7, and a control unit 8. In this specification, the metal pipe material 40 refers to a hollow article before molding is completed in the molding device 103. The metal pipe material 40 is a pipe material made of a steel type that can be hardened. In addition, among the horizontal directions, the direction in which the metal pipe material 40 extends during molding may be referred to as the "longitudinal direction," and the direction perpendicular to the longitudinal direction may be referred to as the "width direction."

[0022] The forming die 102 is a die for forming a metal pipe from the metal pipe material 40, and includes a lower die 11 and an upper die 12 that face each other in the vertical direction. The lower die 11 and the upper die 12 are made of steel blocks. Each of the lower die 11 and the upper die 12 has a recess for accommodating the metal pipe material 40. When the lower die 11 and the upper die 12 are in close contact with each other (closed state), each recess forms a space of the target shape for forming the metal pipe material. Therefore, the surface of each recess becomes the forming surface of the forming die 102. The lower die 11 is fixed to a base 13 via a die holder or the like. The upper die 12 is fixed to a slide of the drive mechanism 3 via a die holder or the like.

[0023] The drive mechanism 3 is a mechanism that moves at least one of the lower mold 11 and the upper mold 12. In Fig. 2, the drive mechanism 3 is configured to move only the upper mold 12. The drive mechanism 3 includes a slide 21 that moves the upper mold 12 so that the lower mold 11 and the upper mold 12 are aligned with each other, a pull-back cylinder 22 as an actuator that generates a force that pulls the slide 21 upward, a main cylinder 23 as a drive source that pressurizes the slide 21 downward, and a drive source 24 that applies a drive force to the main cylinder 23.

[0024] The holding unit 4 is a mechanism for holding the metal pipe material 40 disposed between the lower mold 11 and the upper mold 12. The holding unit 4 includes a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 at one end of the forming mold 102 in the longitudinal direction, and a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 at the other end of the forming mold 102 in the longitudinal direction. The lower electrode 26 and the upper electrode 27 on both sides in the longitudinal direction hold the metal pipe material 40 by sandwiching the vicinity of the end of the metal pipe material 40 from above and below. Grooves having a shape corresponding to the outer peripheral surface of the metal pipe material 40 are formed on the upper surface of the lower electrode 26 and the lower surface of the upper electrode 27. The lower electrode 26 and the upper electrode 27 are provided with drive mechanisms (not shown) that allow them to move independently in the vertical direction.

[0025] The heating unit 101 heats the metal pipe material 40. The heating unit 101 is a mechanism that heats the metal pipe material 40 by passing electricity through the metal pipe material 40. The heating unit 101 heats the metal pipe material 40 between the lower mold 11 and the upper mold 12, while the metal pipe material 40 is separated from the lower mold 11 and the upper mold 12. The heating unit 101 includes the lower electrode 26 and the upper electrode 27 on both sides in the longitudinal direction, and a power source 28 that applies current to the metal pipe material 40 via these electrodes 26, 27.

[0026] Here, the state in which the metal pipe material 40 is arranged inside the forming die 102 means a state in which the metal pipe material 40 is arranged in the space between the upper die 12 and the lower die 11, which face each other. In this state, the metal pipe material 40 faces the upper die 12 while being spaced downward from the upper die 12, and faces the lower die 11 while being spaced upward from the lower die 11.

[0027] The fluid supply unit 6 is a mechanism for supplying high-pressure fluid into the metal pipe material 40 held between the lower mold 11 and the upper mold 12. The fluid supply unit 6 supplies high-pressure fluid to the metal pipe material 40, which has been heated in the heating unit 101 to a high temperature, to expand the metal pipe material 40. The fluid supply unit 6 is provided on both longitudinal ends of the forming die 102. The fluid supply unit 6 includes a nozzle 31 that supplies fluid into the interior of the metal pipe material 40 from an opening at the end of the metal pipe material 40, a drive mechanism 32 that moves the nozzle 31 back and forth relative to the opening of the metal pipe material 40, and a supply source 33 that supplies high-pressure fluid into the metal pipe material 40 through the nozzle 31. The drive mechanism 32 brings the nozzle 31 into close contact with the end of the metal pipe material 40 while ensuring a seal when supplying or discharging fluid, and moves the nozzle 31 away from the end of the metal pipe material 40 at other times. The fluid supply unit 6 may supply a gas such as high-pressure air or an inert gas as the fluid. The fluid supply unit 6 may be integrated into the holding unit 4 having a mechanism for moving the metal pipe material 40 in the vertical direction, and may also be integrated into the heating unit 101.

[0028] The cooling unit 7 is a mechanism for cooling the forming die 102. By cooling the forming die 102, the cooling unit 7 can rapidly cool the expanded metal pipe material 40 when it comes into contact with the forming surface of the forming die 102. The cooling unit 7 includes flow paths 36 formed inside the lower die 11 and the upper die 12, and a water circulation mechanism 37 that supplies cooling water to the flow paths 36 and circulates the water.

[0029] In this way, the forming die 102 is provided with a quenching mechanism 105 that quenches the formed product 140. The quenching mechanism 105 is composed of the forming surface of the forming die 102 and the cooling unit 7.

[0030] The control unit 8 is a device that controls the entire molding device 103. The control unit 8 controls the drive mechanism 3, the holding unit 4, the heating unit 101, the fluid supply unit 6, and the cooling unit 7. The control unit 8 repeatedly performs the operation of molding the metal pipe material 40 in the molding die 102.

[0031] The control unit 8 controls the drive mechanism 3 to lower the upper die 12 and bring it close to the lower die 11, thereby closing the forming die 102. Meanwhile, the control unit 8 controls the fluid supply unit 6 to seal the openings at both ends of the metal pipe material 40 with the nozzle 31 and supply fluid. As a result, the metal pipe material 40, softened by heating, expands and comes into contact with the forming surface of the forming die 102. The metal pipe material 40 is then formed to conform to the shape of the forming surface of the forming die 102. When a metal pipe with a flange is formed, a portion of the metal pipe material 40 is inserted into the gap between the lower die 11 and the upper die 12, and then the die is closed to crush the inserted portion and form a flange portion. When the metal pipe material 40 contacts the forming surface, it is quenched by the forming die 102, which is cooled by the cooling unit 7, thereby quenching the metal pipe material 40.

[0032] 3 may be employed as the forming device 103. The forming device 103 shown in Fig. 3 is a device that performs forming and quenching by bringing a heated flat-plate metal material 50 into contact with the forming surface of a forming die 102. This forming device 103 includes a heating unit 101.

[0033] The molding device 103 includes a molding die 102 that molds the metal material 50 to form a molded product. The molding die 102 includes an upper die 62 that contacts the upper surface of the metal material 50 and a lower die 63 that contacts the lower surface of the metal material 50. The molding surface (lower surface) of the upper die 62 and the molding surface (upper surface) of the lower die 63 may be formed into a shape corresponding to, for example, a hat shape. The molding device 103 includes a drive unit (not shown) that moves at least one of the upper die 62 and the lower die 63. The molding device 103 molds the metal material 50 into the shape of the molded product by sandwiching the metal material 50 between the molding surface of the upper die 62 and the molding surface of the lower die 63. Note that the configuration of the molding die 102 is not limited to a configuration in which the dies are arranged vertically opposite each other, such as the upper die 62 and the lower die 63, but may also be arranged horizontally opposite each other. Furthermore, the number of dies constituting the molding die 102 is not limited to two and may be divided into three or more.

[0034] The heating section 101 heats the metal material 50 placed inside the molding die 102. Here, the state in which the metal material 50 is placed inside the molding die 102 is the same as that shown in Fig. 2, and refers to a state in which the metal material 50 is placed in the space between an upper mold 62 and a lower mold 63 that face each other.

[0035] The heating unit 101 heats the metallic material 50 by passing a current through the metallic material 50. Specifically, the heating unit 101 includes a pair of electrodes 70A, 70B and a power source 71. The electrodes 70A, 70B are members that come into contact with the metallic material 50 and pass a current through the metallic material 50. As a result, the metallic material 50 itself generates heat through Joule heat due to the electrical resistance of the metallic material 50 (electrical heating). The power source 71 is connected to the electrodes 70A, 70B and passes a current through the metallic material 50 via the electrodes 70A, 70B.

[0036] In the example shown in FIG. 3 , the electrodes 70A and 70B are in contact with the longitudinal ends of the metal material 50. The arrangement in which the electrodes 70A and 70B contact the metal material 50 is not particularly limited. The electrodes 70A and 70B may have the function of holding the metal material 50, but a holding mechanism other than the electrodes 70A and 70B may also be provided separately. The arrangement in which the electrodes 70A and 70B are provided relative to the molding device 103 is not particularly limited. For example, the electrodes 70A and 70B may be attached to the molding die 102. In this case, the electrodes 70A and 70B may be removed from the molding die 102 when the electrical heating is completed and the upper mold 62 and the lower mold 63 are closed. Alternatively, the electrodes 70A and 70B may be positioned away from the molding die 102 so as not to interfere with the electrodes 70A and 70B even when the upper mold 62 and the lower mold 63 are closed. Furthermore, electrodes 70A and 70B may be provided with actuators (not shown) so that electrodes 70A and 70B can be configured to be movable relative to molding die 102.

[0037] 2, the molding system 100 includes a control unit 80. The control unit 80 is a device that controls the entire molding system 100. The control unit 80 is electrically connected to a power source 71 of the heating unit 101. The control unit 80 controls the timing of heating by the heating unit 101 by sending a control signal to the power source 71, and also controls the heating temperature by adjusting the magnitude of the current.

[0038] The molding system 100 may have the configuration shown in FIG. 4 . In the molding system 100 shown in FIG. 4 , the heating unit 101 and the molding device 103 are provided as separate devices. This allows the heating unit 101 to heat the metal pipe material 40 outside the forming mold 102. At this time, the heating unit 101 heats the metal pipe material 40 to point A3 or higher, i.e., to 800°C or higher. The state in which the heating unit 101 performs heating outside the forming mold 102 refers to a state in which heating is performed outside the space facing the dies 12 and 11. In the example shown in FIG. 4 , the heating unit 101 is provided at a different position from the molding device 103. The metal pipe material 40 heated by the heating unit 101 is then set in the molding device 103 by a transport device such as a robot hand (not shown). The other configurations of the molding device 103 are similar to those of the molding device 103 shown in FIG. 2 . In addition, even in the molding system 100 for molding the flat metal material 50 as shown in FIG. 3, the heating unit 101 may be configured to heat the molding die 102 outside.

[0039] Returning to Fig. 1 , the cooling mechanism 104 is a mechanism that cools the molded product 140. As shown in Fig. 4 , the cooling mechanism 104 is provided at a position separate from the quenching mechanism 105. In this embodiment, the cooling mechanism 104 is provided at a position separate from the molding die 102, outside the molding die 102. The molded product 140 is transported to the cooling mechanism 104, which is separate from the quenching mechanism 105, during quenching by the quenching mechanism 105.

[0040] The cooling mechanism 104 may be a cooling jig 110 that cools the molded article 140. The cooling mechanism 104 includes an upper jig 111 that receives the molded article 140 after molding, and a lower jig 112. The upper jig 111 and the lower jig 112 sandwich the molded article 140, thereby removing heat from the molded article 140 at points of contact with the molded article 140.

[0041] A specific example of the cooling jig 110 will be described with reference to FIGS. 5 and 6. As shown in FIGS. 5(a) and 6(a), the jig 110 has mold-type members, as an upper jig 111 and a lower jig 112, each having a contact surface 117 that corresponds to the outer peripheral surface of the molded product 140. A cooling circuit 116 through which a refrigerant flows is provided inside the upper jig 111 and the lower jig 112. The cooling circuit 116 is embedded inside the mold and extends longitudinally around the contact surface 117. As a result, the upper jig 111 and the lower jig 112 cool the molded product 140 by bringing the contact surface 117, which has been cooled by the cooling circuit 116, into contact with the molded product 140.

[0042] As shown in Figures 5(b) and 6(b), the jig 110 has an upper jig 111 and a lower jig 112, which are members of a type configured with a plurality of ribs 118. As shown in Figure 6(b), the upper jig 111 and the lower jig 112 have a plurality of ribs 118 arranged in a lattice pattern, forming an internal space 119 corresponding to the molded product 140. As a result, the upper jig 111 and the lower jig 112 bring each rib 118 into contact with the molded product 140 in the internal space 119, and cool the molded product 140 by dissipating heat from each rib 118. Note that cooling of the molded product 140 may be promoted by directly flowing a cooling medium (such as water) between the ribs 118.

[0043] Referring to Figure 7, the cooling process of each process is shown on a CCT diagram. Graph G1 shows the relationship between temperature and time when only the forming device 103 is used and the formed product 140 is cooled to the Mf point in the forming mold 102 after forming. In the process of graph G1, the formed product 140 is cooled in the forming mold 102, so the forming device 103 is occupied for a long time per formed product 140. Graph G2 shows the relationship between temperature and time when the formed product 140 is removed from the forming mold 102 after forming and allowed to cool naturally in air. In this case, the cooling rate of the formed product 140 in the atmosphere is slow, so a martensitic structure is not obtained and deformation due to transformation occurs.

[0044] In contrast, graph G3, which represents the process according to this embodiment, shows the relationship between temperature and time when the molded product 140 is transported after molding and cooled by the cooling mechanism 104. When the molded product 140 is cooled by the quenching mechanism 105 of the forming mold 102, graph G3 plots similar to graph G1 (PT1). During transport of the molded product 140, graph G3 plots similar to graph G2 (PT2). When the molded product 140 is cooled by the cooling mechanism 104, graph G3 plots a rapid temperature drop with a similar slope to graph G1 (PT3). The cooling mechanism 104 rapidly cools and freezes the molded product 140 to the Mf point, thereby obtaining a martensitic structure and suppressing deformation. Furthermore, because the molded product 140 is removed after molding by the forming mold 102, the time the molding device 103 occupies per molded product 140 is shortened, improving throughput. In other words, in this embodiment, the workpiece is transferred to another cooling mechanism 104 while being cooled in the quenching mechanism 105, and is cooled to the martensitic transformation start temperature and the martensitic transformation finish temperature in the other cooling mechanism. This improves throughput while obtaining a martensitic structure even during quenching.

[0045] Next, the operation and effects of the molding system 100 according to this embodiment will be described.

[0046] In the molding system 100, the molding device 103 is provided with a quenching mechanism 105 that quenches the molded product 140. Therefore, immediately after molding, the molded product 140 is rapidly cooled by the quenching mechanism 105. Here, the molded product 140 is transported to a cooling mechanism 104 separate from the quenching mechanism 105 while being quenched by the quenching mechanism 105. As a result, the molded product 140 is rapidly cooled by the cooling mechanism 104, thereby completing the quenching. Therefore, the desired strength of the molded product 140 can be obtained by quenching. Furthermore, the cooling mechanism 104 is a mechanism separate from the quenching mechanism 105. Therefore, the throughput until the molded product 140 is removed from the molding die 102 is shortened, and the quenching mechanism 105 of the molding die 102 can mold the next metal pipe material 40. As described above, the molding throughput can be shortened while obtaining the desired strength of the molded product 140.

[0047] After being transported to the separate cooling mechanism 104, the metal pipe material 40 may be cooled from the martensitic transformation start temperature to the martensitic transformation finish temperature, thereby completing the quenching of the metal pipe material 40 in the separate cooling mechanism 104.

[0048] The cooling mechanism 104 may be a cooling jig that cools the molded product 140. In this case, the cooling mechanism 104 can cool the molded product 140 at a location separate from the molding die 102. Therefore, as shown in Figure 8, it is not necessary to provide the cooling mechanism 104 separate from the quenching mechanism 105 in the molding die 102 itself.

[0049] Here, a molded product 140 as shown in FIG. 9 will be described. The molded product 140 shown in FIG. 9 includes a pipe body 141 and a pair of flanges 142. The pipe body 141 has flat portions 141a and 141b and side portions 141c and 141d. The flanges 142 are formed by crushing a portion of the metal pipe material 40. In this molded product 140, the cooling rate of the curved portions, measurement points P2 and P4, is slower than the temperatures of measurement points P3 and P5 on the flat portions 141a and 141b. The temperatures of measurement points P2 and P4 reach the same temperature as measurement points P3 and P5, taking approximately 1.5 seconds, which is slower than the cooling time of measurement points P3 and P5. FIG. 10 shows the relationship between the temperatures of the flat portions 141a and 141b of the molded product 140 after air blowing and the blow retention time in the mold, depending on the blow pressure. When the blow pressure is high (25 MPa), the temperature remains below 200° C. regardless of the holding time, but when the blow pressure is low and the holding time is short, the temperature does not drop below 200° C. Therefore, depending on the shape of the molded product 140 and the molding conditions, if cooling ends before the molded product is sufficiently cooled, warping will occur due to differences in the amount of thermal shrinkage.

[0050] In contrast, when there are areas with a slow cooling rate, such as the molded product 140 in FIG. 9 , or when the blow pressure cannot be increased due to manufacturing constraints, using the cooling mechanism 104 of the molding system 100 according to this embodiment can shorten the time the molding device 103 is occupied, and sufficient cooling can suppress warpage due to differences in thermal contraction. For example, FIG. 11A is a graph showing the relationship between the cooling method and time for a molded product for a comparative example in which cooling is performed using only the mold 102, and an example in which cooling is performed using both the mold 102 and the cooling mechanism 104. This graph shows the time it takes for the molded product to cool to a target temperature (e.g., 200°C) after molding. In the comparative example, the entire cooling process is performed using only the mold 102 over a time t1 (e.g., 40 seconds). In contrast, in the example, cooling is performed using the mold 102 over a time t2 (e.g., 30 seconds), which is shorter than the time t1, and the molded product is removed from the mold 102. At this time, the molded product has not yet cooled to the target temperature. Next, the temperature is cooled by the cooling mechanism 104 over a time t3 until the temperature drops to the target temperature.

[0051] Here, depending on the shape of the molded product 140 to be molded, the blow pressure in the molding device 103 may not be increased due to manufacturing condition constraints. When the blow pressure is low, it takes time to cool the molded product to the desired temperature, as shown in FIG. 10 . Therefore, for metal pipe material 40 with low blow pressure in the molding device 103, the ratio of the cooling time in the cooling mechanism 104 to the cooling time in the mold 102 may be increased compared to the case of metal pipe material 40 with high blow pressure. In this case, the shape of the metal pipe material 40 with low blow pressure can be firmly frozen. Specifically, FIG. 11( b) is a graph showing the ratio of the cooling time in the mold 102 and the cooling time in the cooling mechanism 104 relative to the total cooling time. As shown in FIG. 11( b), the ratio of the cooling time in the cooling mechanism 104 to the cooling time in the mold 102 under "low blow pressure" is higher than that under "high blow pressure."

[0052] The present disclosure is not limited to the above-described embodiments. For example, the molding devices shown in Figures 2 to 4 are merely examples, and the molding device may have any configuration as long as it does not deviate from the spirit of the present disclosure.

[0053] For example, as shown in Fig. 8 , the quenching mechanism 105 and the cooling mechanism 104 may be provided at different positions within the same forming die 102. In this case, it is not necessary to reserve space for providing the cooling mechanism 104 at a location other than the forming die 102. Specifically, as shown in Fig. 8(a) , the forming surface 55 of the quenching mechanism 105 and the contact surface 117 of the cooling mechanism 104 are formed within one forming die 102. Once forming by the quenching mechanism 105 is completed (see Fig. 8(a) ), the molded product 140 is transported to the adjacent cooling mechanism 104 (see Fig. 8(b) ). Then, the mold is closed, and the molded product 140 is sandwiched between the mold 12 and the mold 11 and cooled by the cooling mechanism 104 ( Fig. 8(c) ).

[0054] In this embodiment, in addition to the metal pipe material, metal materials such as metal plates can also be used.

[0055] 100...forming system, 101...heating section, 102...forming mold, 103...forming device (forming section), 104...cooling mechanism, 105...quenching mechanism, 110...jig.

Claims

1. A heating section for heating metal pipe material, The system comprises a molding section for shaping the heated metal pipe material with a mold, The molding section is provided with a heat treatment mechanism for heat treatment of the molded product. A molding system in which the molded product is transported to a cooling jig provided outside the mold during the quenching process by the quenching mechanism.

2. The molding system according to claim 1, wherein, after being transported to the aforementioned separate cooling mechanism, the metal pipe material is cooled from the martensitic transformation start temperature to the martensitic transformation end temperature.

3. In the molding section, molding is performed by supplying fluid to the metal pipe material and causing it to expand. The molding system according to claim 1, wherein, in the case of the metal pipe material with a low blow pressure in the molding section, the ratio of the cooling time in the cooling mechanism to the cooling time in the molding die is increased compared to the case of the metal pipe material with a high blow pressure.